Transmission



April 7, 1936.

W. A. GARRATT TRANSMISSION Filed March 8, 1935 2 Sheets-Sheet l INV TOR. I

*Wm/x M ATTORNEY:

n I l l l l Il April 7, 1936. Y w A ARRATT l2,036,626

TRANSMI SSION Fil'ed March 8, 1935 2 Sheets-Sheet 2 ATTORNEY BY-mwr Patented Apr. 7, 1936 UNITED STATES PATENT OFFICE TRANSMISSION Walter A. Garratt, Covington, Ky. Application March 8, 1935, Serial No. 10,024

' 1s claims. (C1. 'i4- 117) This invention relates to improvements in transmissions, particularly variable speed transmissions of the character disclosed in my copending application Serial Number 632,407, led September 9, 1932, of which this application is a continuation in part.

The construction disclosed in the co-pending case incorporates a variable throw eccentric system surrounded by a xed throw eccentric system with motion from one to the other accomplished through members interposed between them, the relative speed of one system to the other being relative to the throw of the variable throw system. l

It is the object of the present invention to provide an improved transmission of this character in which the mechanism operates with less friction, provides a smoother ow of power in which the parts yof the clutching mechanismare more rugged, and by means of which a wider range of output speeds may be delivered.

Other objects and further advantages will be more fully apparent from a description of the accompanying drawings, in which:

Figure 1 is a vertical cross sectional view of the machine taken longitudinal of the main axis thereof.

Figure 2 is a cross sectional view taken on line 2 2, Fig. 1, certain of the parts being omitted so that the structure shown may be more clearly illustrated. f

Figure 3 is an end view of a crank shaft.

Figure 4 is a cross sectional view taken on line 4 4, Fig. 1.

Figure 5 is a section on line 5 5, Fig. 2.

Power may be applied at either end of this machine and taken oi at the other, but in the preferred operation of this disclosure the-drive shaft is shown at I0.

The housing or frame for the mechanism is composed of three members, a central tubular member 6, provided with a base 1, an input end plate 8 and an output end plate 9. The drive shaft l0 is provided with a ysuitable coupling II for attachment to av motor or other source of power and is rotatably mounted in a sleeve I6 which is journalled in ball bearings Il in the end plate 8 of the frame. The driven shaft i8 is provided with a key I9 for power take-olf. The shaft I8 is hollow and is provided with an oil stop plug 20. It is journalled in ball bearings l1 in the end plate 3. The inner end of the driven shaft I8 contains the roller bearing 2l which forms a journal for the inner end of the drive shaft I0, so that the two shafts have a common axis, which is hereafter called the main axis.

On the drive shaft In between its journals are formed eccentric lobes 22, upon which lobes is rotatably mounted an eccentric bushing or cylinder 23. The eccentric bushing is hollowed out between the lobes for lessening its weight, and its eccentricity to its bore is the same as the eccentricity of the lobes 22 to the main axis. It is evident that rotating the bushing 23 relative to the lobes 22 varies the eccentricity of the bushing 23 to the main axis through a range between zero and maximum eccentricity and the maximum eccentricity is twice the eccentricity of the lobes 22 to the main axis.

Adjacent to the outside lobes 22 are two other eccentric lobes 24 and 25, the first formed on the shaft I0 and the second constituted by a separate piece but fixed to the shaft by a key. These lobes 24 and 25 have the same amount of eccentricity as the lobes 22 but are positioned in the opposite direction from the lobes 22. The dimension of each of the lobes 24 and 25 measured parallel to the main axis is twice that of the similar dimension of each lobev 22 so that the two lobes 24 and 25 counterbalance the four lobes 22.

Rotatably mounted on the it rotatively in the shoes 30 and 3|, slidably engaged in radial grooves 32 and 33 of the counterweights 26 and 21. These counterweights 26 and 21 are so designed that their centers of mass are eccentric to their bores by the same amount as the bushing 23 is eccentric to its bore. The directions of eccentricity of the bushing and of the counterweights are opposite to each other. The two counterweights are of substantially the same weight as bushing 23 and associated parts. When 'the bushing 23 is rotated relative to the lobes 22,

the counterweights are rotated relative to the lobes 24 and 25. counterbalanced by the lobes 24 and 25, and the bushing 23 is counterbalanced by the counterweights 26 and 21,` whatever the position of eccentricity of the bushing 23.

The sleeve I6 is iianged at the inner end and in the flange is fixed pin 34 on which a shoe 35 Therefore, the lobes 22 are is rotatively mounted. The shoe 35 is slidably mounted in a radial groove in the counterweight 2E. The sleeve i6, therefore, has a connection with the bushing 23 through pin 34, shoe 35, counterweight 2B, shoe 30, pin 28 and bushing 23. Therefore, rotation of the sleeve I6 relative to shaft I0 will rotate bushing 23 relative to 55 :liciently larger in diameter shaft l!! and so change the throw of the eccentric bushing 25 relative to the main axis. This throw is4 maintained constant if there is no rotation of the sleeve It relative to shaft Outside of the end plate d, to the sleeve it, and a collar 3l is keyed to the shaft lll. The collar 3l' has in it a pluralityr of holes tls, in this case 15,- disposed parallel to the main axis disposed equidistant from each other adjacent to the circumference. The collar 3@ has sixteen holes at parallel to the main axis disposed equidistant from each other and their centers are the same distance from the main axis as the holes in collar 3l. The holes in collar 3S are threaded to receive the bolt @t which is tted ,with washer 39, whereas the holes in el are sufthan the bolt @t so that whatever position of the sleeve it relative to shaft lll is selected or, in other words, whatever throw of the eccentric bushing 23 is selected there will be found one or more holes in one collar nearly enough coaxial with a hole in the other collar toallow the bolt et to be entered and tightened so that the collars cannot rotate relative to each other and the eccentric throw is thereby maintained. 'To change the throw the bolt t8 'must be taken out and the collars rotated g relative to each other.

Surrounding the bushing 23, but not touching that, t2, et, it and d5, which are duplicates of each other. The plates are suspended eccentric to the main axis by three crank shafts it, lil and t8, duplicates of each other, extending. through all of them. Each crank shaft has six crank portions or equal throws, one in the plane of each plate, disposed symmetrically about the crank shaft axis as shown in Figure 3. The length of the throw is preferably more than the maximum eccentricity of the bushing 23 to themain axis.

Each crank shaft has a gear secured thereto by a pin 49 near the driven shaft end, respectively gears 50, 5I and 52. These three gears are meshed with a gear 53 formed on the driven shaft I8 concentric to the driven shaft. These gears are so meshed that crank portions of the three crank shafts in the same plane extend always in exactly the same direction from the crank shaft axis or, in other words, the radii of eccentricity of any three crank pins in the same plane are always parallel to each other. This arrangement constrains the six plates so that they are always disposed symmetrically about the main axis. The movement of each plate is limited to pseudo-rotation (wherein the body does not rotate on its center but the center revolves about another point), and force applied to move any one moves all.

The crank shafts are joui-nailed in the end plates .8 and 9 in ball bearings 55. A nut 55 on each crank shaft adjacent ball bearing against an appropriate shoulder of the crank shaft. At one end of each crank shaft the outer race of the ball bearing is held in place by a ring plate Sbyscrews 5l and a thrust cap 58 held against the end plate 9 by screws 59. The vibration which tends to resul-t from the rotation of the crank shafts together with the mass of the pseuit, are six plates do-rotating eccentric plates is substantially nulll.

ed by the crank shaft counterweights Sil loaded with lead and located by set screws 6l. The crank portions of the crank shafts are journalled in the eccentric plates by roller bearings 62 retained in position by washers and spacers 6e, 6d

conn se is keyed end holds the inner race of the' 55 held against the end4 aosaeee i and 65. A spacer washer 66 is inserted between ball bearing' 5:4 and the hub of the gear 50.

Fitting rotatively about the eccentric bushing 23 are six driving collars, duplicates of each other, 6l, Ec, B9, lll, li and '12, interposed between the bushing 23 and the six eccentric plates to, 4 i, 42, 53, 4t and t5, one for each plate in substantially the same plane as its corresponding plate. The driving collars as shown by 6l in Figure 2,' have projections' 'E3 in the end of each of which is fitted rotatively a wedge member. lt. The description of the one collar 6l and its associated partsis the same for the other collars et, 69, lo, ll and 'l2 with their associated parts, which are not shown. The surface of the wedge vmember lo toward the main axis has its bearing in the projection 'lt of the driving collar el and on its opposite surface is formed a wedge shaped groove bearing against the annular wedge surface l5 formed at the circumference of the central hole in the eccentric plate tit.

On one side of the driver collar el is attached a spring lo lying in the same plane as the driver collar and its associated eccentric plate. To the outer end of the spring is attached a clevis il in which is mounted, rotatively on a pin lt, a roller l@ which bears against the circumference of the central hole of the eccentric plate til. Now the distance from the center of the wedge shaped surface of the wedge member it to the center of the driver collar which is the center of the bushing 23 is less than the sum of the radius of the central hole of the eccentric plate and the eccentricity of the eccentric plate to the main axis and more than the difference.

If the drive shaft 2t has zero eccentricity to the main axis there will be no motion imparted to the driver collar. If the bushing 23 is set at Vany selected eccentricity to the main axis, then the bushing 23 will press upon the driver collar in the region of the projection 'i3 when the movement of the center of the bushing in its path about the main axis is in the direction of ythe wedge member 'le and will press through the spring i6 against the roller 19 when its movement is in the other half of its path. When the eccentric bushing presses through the driver collar 5l against the wedge member 'N the driver collar and wedge member become a driving connection between the bushing 23 and the eccentric plate ttl and the rotative movement of the eccentric bushing is translated to pseudo-rotation of the eccentric plate. When the driving stroke is completed the bushing 23 begins to press against the side of the collar opposite to the wedge member le which causes the roller 19 to press against the plate It.

Because of the relation of the center of the eccentric plate il to the center of the eccentric bushing 23, the pressure on the roller 1S causes the driver collar tl to rotate on thecenter of the bushing 23, thus maintaining contact of the wedge member 14 with the eccentric plate 40. Rotation cf the driving collar 6l continues until the pressure of the bushing 23 on the driver collar crosses back to the region of the projection 13 when driving connection is formed again.

This action may be better understood ii it is remembered that the variable eccentricity of the bushing 23 is always less than the ixed eccentricity of the eccentric plates. In observing the action it is also seen that the center of the bushing 23 never crosses a line' drawn through the wedge member lt and the center of the eccentric plate is rotated and the bushing the speed of movement of one 40. If now it is remembered that the segments of the bushing 23 lying each in the plane of one eccentric plate have only one direction of eccentricity whereas the directions of eccentricity of the plates are symmetrically distributed around the main axis, then it is evident thatsome plate is always in position to receive the drive and since plate causes all to move, continuous motion of pseudo-rotation of the eccentric plates results from continuous rotation of the bushing 23 with the drive shaft I0 and the rate of pseudo-rotation is related to the throw of the eccentric, the drive shaft having a constant speed of rotation. e

vThe pseudo-rotation of eccentric plates obviously causesi the same speed of rotation of the three crank shafts and this rotation is transferred through the gears to the driven shaft and the driven shaft bears a fixed ratio to the speed of pseudo-rotation of the eccentric plates, the same as the ratio of the three crank shaft gears 50, i and 52 to the driven shaft gear 53.

Therefore, with a constant rate of rotation of the drive shaft, the rate of rotation of the driven shaft may be varied infinitely from zero to a maximum, which maximum is a ratio of the rate of rotation of the drivev shaft determined by the two factors: first, the ratio of the maximum throw of the variable throw eccentric to the throw of the fixed throw eccentric, and second, the ratio y a drive member'. journail frame,

of the crank shaft gears to the driven shaft gear.

Having described my invention, I claim: 1. In a device of the class described, a frame,

member and adapted to be rotated thereby, ymeans for varying the throw of the variable throw eccentric member, a plurality of fixed throw eccentric members surrounding the variable throw eccentric member and spaced .apart therefrom, members interposed between the variable throw eccentric member and the fixed throw eccentric members for communicating motion from the variabl'e throw eccentric member to the fixed throw eccentric members, cranks rotatably mounted in,

rality of fixed throw eccentric members surrounding the variable throw eccentric member and spacedapart therefrom, said fixed throw eccentric -members arranged in symmetrical phase relationship to the variable throw eccentric members, means for communicating motion from the variable throw eccentric member to the xed throw eccentric members, cranks rotatablymounted in the frame, said fixed throw eccentric members mounted on the cranks and in drivin'gconnection therewith, a driven member journalled in the and gears associated with the cranks and the driven member for communicating motion from the cranks to the driven member.

3. In a device of the class described, a frame, ed therein, a variable throw eccentric member associated with the drive member and adapted to be rotated thereby, means for varying the throw of the variable throw eca drivel member journalled therein, a variablew throw eccentric member associated with the drive 3 centric member, a plurality of fixed throw eccentric members surrounding the variable throw eccentric member and spaced apart therefrom, members interposed between the variable throw eccentric member and the fixed throw eccentric members for communicating motion from the variable'- throw eccentric member to the fixed throw eccentric members, there being one'interposed member for each element of the plurality of fixed throw eccentric members and the corresponding surrounded portion of the variable throw eccentric member, the three being in the same plane, cranks rotatably mounted in the frame, said fixed throw eccentric members mounted on the cranks and in driving connection therewith, a driven member journalled in the frame, and gears associated with the cranks and the driven member for communicating motion from the cranks to the driven member.

4. In a device of the class described, a frame, a drive member journalled therein, a variable throw eccentric member associated with the drive member and adapted to be rotated thereby, means member and adapted to be rotated thereby, means for varying the throw of the variable throw ec a plurality of 'fixed throw ecsurrounding the variable throw eccentric member and spaced apart therefrom,

members interposed between the variable throw eccentric member and the fixed throw eccentric member, the three being in the same plane, cranks rotatably mounted in said frame for receiving the drive from the fixed throw eccentric members, said fixed throw eccentric members mounted on said cranks, said cranks journalled therein, a variableV maintaining a symmetrical phase relationship between the fixed throw eccentric members and the variable throw eccentric member throughoutthe operating cycle and constraining the motion of the xed throw eccentric members to pseudo-ro'- tation wherein the members. are non-rotative but their centers revolve about an axis, a driven member journalled in the frame, and' gears associated with the cranks and the driven member for communicating motion from the cranks to the driven member.

` 6. in a device or the class described, a frame, a drive member journalied therein, a variable throw eccentric member associated' with the drive i member and adapted to be rotated thereby, means for varying the throw of the variable throw eccentric member, a plurality of xed throw eccen-l tric members surrounding thevariable throw eccentric member and spaced apart therefrom, members interposed between the variable tluow eccentric member and the xed throw eccentric members for communicating motion from the variable throw eccentric member to the fixed throw eccentric members, there being one interposed member fcr each element of the plurality of fixed throw eccentric members and the corresponding surrounded portion of the variable throw eccentric member, the three being in the same plane, each interposed member being a driving connection between the variable throw eccentric member and the corresponding surrounding xed throw eccentric member when the variable throw eccentric member presses upon one part of the interposed member and rotating without driving connection when the variable throw eccentric member presses upon any other part of the interposed member not included in the part first mentioned, clutching elements ineluded in each interposed member bearing against the fixed throw eccentric member coupling the interposed member to the :fixed throw eccentric vto member for movement of the two in one direction only, the clutching elements requiring for clutching only a fraction of the force imparted to the interposed member, cranks rotatably mounted in said frame for receiving the drive from the fixed throw eccentric members, said fixed throw eccentric members mounted on said cranks, said cranks maintaining a symmetrical phase relationship between the lfixed throw eccentric members and the variable throw eccentric member throughout the Aoperating cycle and constraining the motion of the iixed throw eccentric member to pseudo-rotation wherein the members do not rotate but their centers revolve about an axis, a driven member journalled in the frame, and gears associated with the cranks and the driven member for communicating` motion from the cranks to the'drivenfmember. i

'7. In a device of the class described, a frame, a drive member journalled therein; a variable throw eccentric memr associated with the drive member and adapted to be rotated thereby, means for varying the throw of the variable throw eccen trict member, a plurality of xed throw eccentric members surrounding the variable throw eccentric member and spaced apart therefrom, members interposed between the variable throw eccentric member and the xed throw eccentric mem-P bers for communicating motion from the variable eccentric member and thro-w eccentric member to the fixed throw eccentric members, each. interposed member being a driving connection between the variable throw the fixed throw eccentric member when the variable throw eccentric member presses upon one part of the interposed mem-1 ber and rotating without driving. connection whenv the variable throw eccentric member presses upon any other part of the interposed member not in` eluded inthe partrst mentioned, clutching parts included in each interposed member bearing against the :fixed throw eccentric member coupling the 'interposed member to the fixed throw bearing against the absence eccentric member for movement of the two in one direction only, cranks rotatably mounted in said trame or receiving the drive from the xed throw eccentric members, said 'fixed throw eccentricl driven member for communicating motion from the cranks to the driven member.

8. ha a device lof the class described, a frame, a drive member journalled therein, a variable throw eccentric member associated with the drive member and adapted to be rotated thereby, means for Y varying the throw ci the variable throw eccentric member, a plurality oi' xed throw eccentric members surrounding the variable throw eccentric Amember and spaced apart therefrom and arranged in symmetrical phase relationship to the variable throw eccentric member, members interposed between the variable throw eccentric member and the fixed throw eccentric members- `or communicating motion from the variable throw eccentric member to the iixed throw eccentric members, there being one interposed member for each element of the plurality of fixed throw eccentric members and the corresponding sur rounded portieri of the Variable throw eccentric member, the three being in the same piane, each interposed member being a driving connection between the variable throw eccentric member and the corresponding surrounding xed throw eccentric member when the variable throw eccentric member presses upon one part of the interposed member and rotating without driving connection when the variable throw eccentric member presses upon any other part of the interposed member not included in the part rst mentioned, clutching elements included in each interposed member iixed throw eccentric member coupling the interposed member to the ixed throw eccentric member for movement of the two in one direction on 5J, the clutch elements requiring for clutching oniy a 'fraction of the force imparted to the interposed member, cranks .rotatably mounted in vsaid frame for receiving the drive from the iixed throw eccentric members, said rixed throw eccentric members mounted on said cranks, said cranks maintaining a Asymmetrical phase relationship between the xed throw eccentric members and the variable throw eccentric member throughout the operating cycle and constraining the motion oi the xed throw eccentric members to psuedo-rotation wherein the members doV not rotate but their centers revolve about -an axis,

a driven member journalied in the frame, and

eating motion from the variable throw eccentric member to the fixed throweccentric members,

' cranks rotatably mounted in the frame, said nxed throw eccentric members mounted on the cranks and in driving connection therewith, a driven member journalled in the frame, and gears associated with the cranks and the driven member for communicating motion from the cranks to the driven member. v

10. In a transmission, a driving shaft, a. driven shaft, a plurality of plates the centers of which are adapted to revolve around the axes ofthe driving and driven shaft, crank shafts supporting said plates in symmetrical arrangement about said axes and confining said plates to revolutionary movement, eccentric means driven by said drive shaft, push arms disposed about said eccentric, one in engagement with the inner periphery of each plate, said push arms engaging the inner periphery of vsaid plates at approximately right angles to the crank arm supports for the plates when in driving contact, and means connecting said crank shafts to said driven shaft.

11. In a device ofthe class described, a frame, a drive member journalled therein, a variable throw eccentric member associated with the drive member and adapted to `be rotated thereby, means for varying the throw of the variable throw eccentric member, counterbalances associated with the variablethrow eccentric member adapted to balance the variable throw eccentric member whatever its eccentricity, a plurality of xed throw eccentric members surrounding the variable throw eccentric member and spaced apart therefrom, members interposed between the variable throw eccentric Jmember and the ilxed throw eccentric members for communicating motion from thevariable throw eccentric member to the xed throw eccentric members, there being one interposed member for each element of the plurality of fixed throw eccentric members andthe corresponding surrounded portion of the variable throw eccentric member, the three being in the same plane, cranks rotatably mounted in the frame, said xed throw eccentric members mounted on the cranks and in driving connection therewith, a driven member journalled in the frame, and gears associated with the cranks and the driven member for communicating motion from the cranks to the driven member.

12. In a device of the class described, a frame, a drive member journalled therein, a variable throw eccentric member associated with the drive member and adapted to be rotated thereby, means for varying the throw of the variable throw eccentric` member, a plurality of xed throw eccentric members surrounding thevariable throw eccentric member and spaced apart.

, therefrom, members interposed between the vavco riable throw eccentric member and the fixed throw eccentric members for communicating motion from the variable throw eccentric member to the xed throw eccentric members, there being one interposed member for each element of the plurality of xed throw eccentric members and the corresponding surrounded portion of the vav riable throw eccentric member, the three being in the same plane, cranks rotatably mounted in the frame, said fixed throw eccentric members mounted on the cranks and in driving connection therewith, counterbalances associated with the crank members adapted to counteract the forces tending to change the position vof the axis of the suspension cranks, a driven member journalled in the frame, and gears associated with the cranks and the driven member for communieatingmotion from the cranks to the driven member.

13. In a device of the class described, a frame, a drive member journalled therein, a variable throw eccentric member associated with the drive member and adapted to be rotated thereby, means for varying the throw of the variable throw eccentric member, counterbalances associated with the variable throw eccentric member.

there being one interposed member for each element of the plurality of xed throw eccentric members and the corresponding surrounded portion of the variable throw eccentric member, the three being in the same plane, cranks rotatably mounted in the frame, said fixed throw eccentric members mounted on the cranks and in driving connection therewith, counterbalances associated with the suspension crank members adapted to counteract the forces tending to change the position of the axis of the cranks, a driven member journalled in the frame, and gears associated with the cranks and the driven member for communicating motion from the cranks to the driven member.

14. In a speed variator, a driving eccentric, means for adjusting the eccentricity of Athe driving eccentric, a plurality of eccentric bodies having their eccentricities symmetrically disposed about the center of rotation of the driving eccentric, rotatable supports for constraining the eccentric bodies to execute pseudo-rotation about the axis of rotation of the driving eccentric, interposed means for transmitting motion from the driving eccentric to the eccentric bodies, a driven member, and means for transmitting motion from the rotatable supports to the driven member. v

15. In a speed variator, a rotatable member, means for adjusting the amplitude of motion of the member to any desired amount within limits, a plurality of pseudo-rotatable members having symmetrical phase relations one with another, mounting elements for constraining the pseudorotatable members to execute pseudo-rotation with reference to the axis of rotation of the rotatable member and to maintain proper and constant phase relationship between the several pseudo-rotative members, a'plurality of intermediate elements one for each pseudo-rotatable member for transmitting motion from the member to the pseudo-rotatable members, a driven member, and means for transmitting motion from the mounting elements to the driven member.

"16. In a speed variator, a driving eccentric, means for adjusting the eccentricity of the driving eccentric, a plurality of eccentric bodies having their eccentricities symmetrically disposed about the center of rotation of the driving eccentric, supports for Vconstraining the eccentric bodies to execute pseudo-rotation about the axis of rotation of the driving eccentric, interposed means for transmitting motion from the driving eccentric to the eccentric bodies, a driven member, and means for transmitting motion from the eccentric bodies to the driven member.

17. In a speed variator, a rotatable member, means for adjusting the throw of said member, a plurality of pseudo-rotatable members having suitable phase relations one with another, mount ing elements for constraining the pseudo-rotatebie members to execute pseudo-rotation with rererence to tile exis of rotation of the rotatable 5 member and to maintain proper end constant phase relationship between the several ris/end@ rotetive members, e plurality of intermediate cie1 ments one for eoch pseudo-rotatable member for transmitting motion from the member to the .10 pseudo-rotatable members, a driven member; and

.means for transmitting motion from the nseudorotatable members to the driven member.

i8. in speed varying concretos, e drive meer ber, e, driven member, e :first eccentric device device including a plurality of elements lironing e. etric'l phase relation to the t 15 rotated by the drive member, a second eccentric Aof the second eccentric device for e xed throw,

e transmission between the xed throw eccentric device ond the driven member, end means `for varying the throw of the verieibieV throw eccentric device.

wir n. GARRAW. 

